Yesterday I registered on Slotella website for testing purposes and I already received $5 bitcointalk welcome bonus on my account.
That wagering requirements could be better, and I don't it's good to have to deposit $100 before you can withdraw anything.
I definitely agree that the wagering requirement should be a must and there is no transfer of the fund from one to another account, there should be a limit to transferring funds into another account. This could be how to protect the user's fund and the gambler and gambling casino as well.
No KYC gambling casino will probably be prone to scamming and abusing players, you should take address it.
However, good to see OP was actively answered all those concerns.